Forms of Light: Infrared Animals

Different wavelengths of light reveal and conceal
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Infrared Animals Interactive

Split screen showing animals outdoors
All animals glow, meerkats brighter than tomistoma
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Visible light provides us with detailed information about our environment, including colors and textures.

Infrared light shows less detail, but the warmth from animal bodies glows dramatically.


A Story Of Forms of Light: Infrared Animals

Different wavelengths of light provide different information.

Human eyes have evolved to detect the rainbow of colors that make up visible light. Some things, like stars and light bulbs, emit their own light. Other things, like plants and animals, are visible because they reflect visible light from other sources. But visible light is just one form of light. There are other types of electromagnetic radiation that human eyes cannot see. Objects that do not give off visible light can glow in other wavelengths, like infrared, which is light that is past the red end of the visible rainbow.

Like humans, other animals have adapted to suit their environments. With our eyes we can see external details like coloration, texture, and markings. Infrared light gives us very different—but still valuable—information, including temperature. The warmest areas glow brightest, and the cool extremities like paws or the tips of scales appear darkest. Infrared also makes clear that the meerkats (left) are much warmer than the tomistoma (right), because the tomistoma is cold-blooded and the meerkats are warm-blooded; in visible light this difference between the two is not detectable. By studying our environment with wavelengths beyond what we see with our eyes, we get different information and a more complete “picture.”

Quick Facts: Infrared Animals

Type: Meerkats (left) and tomistoma (right)

Size: Infrared wavelengths are longer (and less energetic) than visible wavelengths

Did you know: Body heat cannot be detected in visible light, but infrared light shows warmer bodies glowing more brightly.

Explore More About Forms of Light

Find out more with these additional resources from NASA’s Universe of Learning

Credits: Infrared Animals

Visible light images: NASA, IPAC, Los Angeles Zoo

Infrared light images: NASA, IPAC, Los Angeles Zoo

Produced by the Space Telescope Science Institute’s Office of Public Outreach